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ninadavtian.bsky.social
Dr. Nina Davtian (she/her/hers)
@ninadavtian.bsky.social
3.9K followers 2.1K following 550 posts
@cnrs-insu.bsky.social researcher at @climatecerege.bsky.social. Using biomarkers to study climate, ocean, and environment of the past. @icta-uab.bsky.social alumna. ORCID: https://orcid.org/0000-0002-3047-6064 🇫🇷 -> 🇪🇸 -> 🇫🇷
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ninadavtian.bsky.social
Dr. Nina Davtian (she/her/hers) @ninadavtian.bsky.social · Nov 3
Hello! 👋🏻
Trained as a geologist, I do paleo-reconstructions using molecular fossils, aka biomarkers.
My favorite biomarkers are archaeal and bacterial membrane-spanning lipids—glycerol dialkyl glycerol tetraethers, GDGTs.
A 🧵 of 🧵 on my five most significant papers in chronological order: 👇🏻
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White mug with two membrane-spanning lipids drawn on it. The molecule drawn in green is a bacterial membrane lipid whereas the molecule drawn in blue, red, and yellow is a famous archaeal membrane lipid named crenarchaeol. Mug acquired during the 2nd international GDGT workshop on 6–8 September 2023 at ETH Zürich, Switzerland. Photo taken by Nina Davtian (it's me!).
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Reposted by Dr. Nina Davtian (she/her/hers)
icebird.bsky.social
Marlo Garnsworthy @icebird.bsky.social · 2h
Good morning! Here’s your minute of peace & calm.

The sky changes quite a lot in the 10-minute version. Watch here: youtu.be/WcNALnGa2wU?...

#OceanDevotion
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Reposted by Dr. Nina Davtian (she/her/hers)
zacklabe.com
Zack Labe @zacklabe.com · 2h
Substantial losses of #Arctic sea ice concentration are found in October. The largest declining trends extend from parts of the East Siberian Sea to the Chukchi Sea.

Sea ice concentration = fraction of ice-cover. More info on recent Arctic climate: doi.org/10.1175/BAMS...
Graphic showing a polar stereographic map of October 2024 Arctic sea ice concentration anomalies with anomalies from -50% in red shading to +50% in blue shading. More areas are below normal than above normal.
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Reposted by Dr. Nina Davtian (she/her/hers)
The Keeling Curve @keelingcurve.bsky.social · 6h
424.19 parts per million (ppm) CO2 in air 11-Oct-2025
keelingcurve.ucsd.edu
The Keeling Curve
The Keeling Curve is a daily record of global atmospheric carbon dioxide concentration maintained by Scripps Institution of Oceanography at UC San Diego.
keelingcurve.ucsd.edu
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Reposted by Dr. Nina Davtian (she/her/hers)
zacklabe.com
Zack Labe @zacklabe.com · 9h
Unfortunately still no #Arctic sea ice thickness and volume update for the month of September on my website... data issues from the U.S. government shutdown

PIOMAS notice: psc.apl.uw.edu/research/pro...
Screenshot that says "August 2025 Monthly Update [September update delayed due to US Govn’t shutdown resulting in unavailable data]"
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Reposted by Dr. Nina Davtian (she/her/hers)
jonbakerocean.bsky.social
Jon Baker @jonbakerocean.bsky.social · 9h
Always interesting to see this come up again 😄

Our Nature paper didn’t “redefine” collapse — there’s no single threshold, though ~6 Sv is common.

We used 0 Sv only for extreme 4×CO₂ runs (full shutdown).

Under real-world forcing, models stay above 6 Sv this century — no collapse.

Clarified 🌊👇
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Reposted by Dr. Nina Davtian (she/her/hers)
zacklabe.com
Zack Labe @zacklabe.com · 10h
Temperatures were warmer than 5°C above the 1981-2010 average in September 2025 across northern Canada and into the Canadian Arctic Archipelago. The southern route of the Northwest Passage was ice-free and open for transit this past melt season.

Data freely available from doi.org/10.24381/cds...
Regional map of the Canadian Arctic showing September 2025 temperature anomalies. Most areas are warmer than average northeast of Hudson Bay. Anomalies are calculated to a 1981-2010 baseline with red being warmer than average, and blue being colder than average.
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Reposted by Dr. Nina Davtian (she/her/hers)
rahmstorf.bsky.social
Prof. Stefan Rahmstorf @rahmstorf.bsky.social · 12h
High resolution images from satellite and from eddy-resolving ocean circulation models point to an ongoing decline of the Atlantic overturning circulation, a key ocean current for our climate. Read more about it in my new blog article. 🌊
www.realclimate.org/index.php/ar...
RealClimate: High-resolution ‘fingerprint’ images reveal a weakening Atlantic Ocean circulation (AMOC)
The #AMOC is the reason for Europe’s mild climate. Evidence that it is slowing has been piling up over the years – it now is likely at its weakest in at least a millennium, and it may even be approach...
www.realclimate.org
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Reposted by Dr. Nina Davtian (she/her/hers)
zacklabe.com
Zack Labe @zacklabe.com · 21h
September #Arctic sea ice extent since the year 1850 - comparison now updated through 2025

I have a couple of other sea ice reconstructions on my website too: zacklabe.com/arctic-sea-i...
Line graph time series of September Arctic sea ice extent for every year from 1850 through 2025. Two datasets are compared in this time series. The Walsh et al. 2019 reconstruction is shown with a solid blue line. The NSIDC Sea Ice Index v3 is shown with a dashed red line only for the satellite era. There is large interannual variability and a long-term decreasing trend over the last few decades.
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Reposted by Dr. Nina Davtian (she/her/hers)
ianhall.bsky.social
Ian Hall @ianhall.bsky.social · 18h
🌊 A triple planetary crisis now affects every part of the ocean

oceanographicmagazine.com/news/a-tripl...
A triple planetary crisis now affects every part of the ocean - Oceanographic
It's according to the Ninth Copernicus Ocean State Report that every part of the ocean is now affected by the triple planetary crisis.
oceanographicmagazine.com
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Reposted by Dr. Nina Davtian (she/her/hers)
icebird.bsky.social
Marlo Garnsworthy @icebird.bsky.social · 1d
New #OceanDevotion: underwater! 5 minutes in a tide pool.

youtu.be/fYH8PJz6Z-k?...

Who will you see?

Filmed with my DJI Osmo Pro 5
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Reposted by Dr. Nina Davtian (she/her/hers)
icebird.bsky.social
Marlo Garnsworthy @icebird.bsky.social · 1d
Good morning! Here’s your minute of peace & calm.

Trying something new today on YouTube: TWENTY minutes: youtu.be/09vmrbrhx-0?...

What’s your ideal #OceanDevotion length?

Stay tuned for some underwater footage… 👀
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Reposted by Dr. Nina Davtian (she/her/hers)
katharinehayhoe.com
Katharine Hayhoe @katharinehayhoe.com · 1d
This week's Talking Climate is guest-edited by the A of the band AJR. Adam is passionate about climate action and has teamed up with Ticketmaster + more to activate fans in creative new ways.

You won't want to miss this one! Read here: us14.campaign-archive.com?u=fa37a09043...
A screenshot of my Talking Climate newsletter with the headline: "Activating people through music, getting off autopilot, and connecting for change."
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Reposted by Dr. Nina Davtian (she/her/hers)
micefearboggis.bsky.social
John Kennedy @micefearboggis.bsky.social · 1d
D and A and I and H

diagrammonkey.wordpress.com/2025/10/11/d...
D and A and I and H
Detection and attribution is back in the news for all the wrong reasons. Pielke Junior is once again pushing the line that anyone wanting to say anything about extreme weather has to prove all over…
diagrammonkey.wordpress.com
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Reposted by Dr. Nina Davtian (she/her/hers)
alexislicht.bsky.social
Alexis Licht @alexislicht.bsky.social · 1d
A great paper in LeMonde about the work of my friend and colleague Jeremy Martin from @lgltpe.bsky.social, on the discovery of a complete Jurassic crocodile in southern France! www.lemonde.fr/sciences/art...
Un crocodile du Jurassique quasi complet découvert dans l’Hérault
Le squelette de ce fossile de crocodile, datant de 180 millions d’années, a été dévoilé vendredi au Musée de Lodève.
www.lemonde.fr
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Reposted by Dr. Nina Davtian (she/her/hers)
The Keeling Curve @keelingcurve.bsky.social · 1d
423.81 parts per million (ppm) CO2 in air 10-Oct-2025
keelingcurve.ucsd.edu
The Keeling Curve
The Keeling Curve is a daily record of global atmospheric carbon dioxide concentration maintained by Scripps Institution of Oceanography at UC San Diego.
keelingcurve.ucsd.edu
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Reposted by Dr. Nina Davtian (she/her/hers)
bonpote.com
Bon Pote @bonpote.com · 2d
Les médias parlent trop peu d’écologie en France. Surtout, ils parlent de tous les sujets sans faire le lien avec le climat ou la biodiversité. 5%, c’est ridicule, compte tenu des enjeux.

Soutenons la presse indépendante et encourageons les autres médias à faire mieux.
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Reposted by Dr. Nina Davtian (she/her/hers)
zacklabe.com
Zack Labe @zacklabe.com · 1d
Here is a closer look at the record low #Arctic sea ice around Svalbard currently. This coincides with the record warmth as well (check out my earlier post). Earlier last week temperatures in parts of Svalbard were more similar to July than October.

Graphic produced by cryo.met.no/en/sea-ice-i...
Line graph time series of Svalbard sea ice area for 2025 compared to 2012 2020, and the 1981-2010 average with percentiles shown. There is a large seasonal cycle.
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Reposted by Dr. Nina Davtian (she/her/hers)
ianhall.bsky.social
Ian Hall @ianhall.bsky.social · 1d
They’re smaller than dust, but crucial for Earth’s climate

www.sciencedaily.com/releases/202...
They’re smaller than dust, but crucial for Earth’s climate
Coccolithophores, tiny planktonic architects of Earth’s climate, capture carbon, produce oxygen, and leave behind geological records that chronicle our planet’s history. European scientists are unitin...
www.sciencedaily.com
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Reposted by Dr. Nina Davtian (she/her/hers)
ianhall.bsky.social
Ian Hall @ianhall.bsky.social · 1d
New modelling study suggests the deglacial radiocarbon seesaw was driven by weaker Antarctic overturning + lower Southern Ocean reservoir age — not stronger circulation.

Both poles had sluggish deep water flow.

www.nature.com/articles/s41...
Reduced Antarctic Bottom Water overturning rate during the early last deglaciation inferred from radiocarbon records - Nature Communications
Reconstructed radiocarbon ventilation seesaw and reduced Southern Ocean surface reservoir age imply reduced Antarctic Bottom Water overturning parallel to the weakened North Atlantic Deep Water overturning during the early deglaciation.
www.nature.com
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Reposted by Dr. Nina Davtian (she/her/hers)
speleoseb.bsky.social
Seb Breitenbach @speleoseb.bsky.social · 1d
Your wonderful 206Pb/238U clock seems broken? Do not despair, you may be able to fix it using 207Pb/235U! Read here how…. 👇 kudos to Pieter and team, I certainly learned a lot in the process! 🤩😛 gchron.copernicus.org/articles/7/4...

@annabelwolf.bsky.social
@pucicu.de @geochron.bsky.social
Carbonate 206Pb ∕ 238U problems and potential 207Pb ∕ 235U fixes
Abstract. Carbonate U–Pb dating has become a key tool for Quaternary palaeoclimatology and palaeoanthropology beyond the age limit of Th–U disequilibrium dating. U–Pb geochronology is based on the pai...
gchron.copernicus.org
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Reposted by Dr. Nina Davtian (she/her/hers)
icebird.bsky.social
Marlo Garnsworthy @icebird.bsky.social · 1d
I also flew my drone this morning, and you can watch that video here:

youtu.be/h0mdC09o2wo?...

#OceanDevotion
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Reposted by Dr. Nina Davtian (she/her/hers)
zacklabe.com
Zack Labe @zacklabe.com · 1d
Record high temperatures are currently being set across the northernmost portions of the #Arctic. In fact, it is effectively ice-free on the Atlantic side of the Arctic all the way up to about 85°N latitude! This includes record low sea ice around Svalbard.

Graphic by zacklabe.com/arctic-tempe...
Line graph time series of 2025's daily 2-m temperature in the Arctic compared to each year from 1958 through 2024. There is a long-term warming trend for every day of the year. There is also large interannual variability and a clear seasonal cycle.
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Reposted by Dr. Nina Davtian (she/her/hers)
palaeopercs.bsky.social
Pal(a)eoPERCS @palaeopercs.bsky.social · 1d
You can see David's abstract here (with alt text):
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Marine phytoplankton play an important part within the global carbon cycle, removing great amounts of carbon from the atmosphere and producing around half of the atmospheric oxygen today. Furthermore, forming the largest part of the base of aquatic food chains, phytoplankton represent the starting point of biological activities in the oceans. Therefore, the study of ancient phytoplankton dynamics at regional and global scales can provide valuable insights into the evolution of marine ecosystems.
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Reposted by Dr. Nina Davtian (she/her/hers)
palaeopercs.bsky.social
Pal(a)eoPERCS @palaeopercs.bsky.social · 1d
Next week at #PalaeoPERCS we will be joined by David Kröck from University in Shenzhen, China.
Sign up here: paleopercs.com/participate/
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Reposted by Dr. Nina Davtian (she/her/hers)
oceanhelen.bsky.social
Prof Helen Bostock @oceanhelen.bsky.social · 1d
University of Queensland in brisbane is hosting the Plastics 2026 #plastics2026 conference.abstracts open now.
Plastics2026 - A global symposium on plastics and human health | 1-4 March 2026
qaehs.centre.uq.edu.au
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